Test Equipment Anonymous (TEA) group therapy thread

[TERRA Operative]

Yeah, they look close, but I need a type that is tubular so there is clearance for the shaft of the pot.

I'm half thinking of getting a cheap socket and taking to it with a file to notch the end into two pins..

[tggzzz]

Here's a question for the tool aficionados...

I need to tighten the 5-turn knob on a multi-turn pot on my Tek SG504 (same thing is used on other gear like the Tek SG503 etc) and it seems I need a special little socket wrench..

Does anyone know what this sort of thing is called and where I can get one? I swear I've seen them before but I can't get the right keywords to find them in google..
I need one with an OD of about 8mm or so.

If you only want to tighten this once, try using some fine-tipped pliers or the end of a screwdriver. Yes, that's a bodge, but it might be suffficient.

Less of a bodge would be to fabricate that shape from a piece of metal pipe, using a file.

[AVGresponding]

Here's a question for the tool aficionados...

I need to tighten the 5-turn knob on a multi-turn pot on my Tek SG504 (same thing is used on other gear like the Tek SG503 etc) and it seems I need a special little socket wrench..

Does anyone know what this sort of thing is called and where I can get one? I swear I've seen them before but I can't get the right keywords to find them in google..
I need one with an OD of about 8mm or so.

I would use circlip pliers, like these:

[tautech]

Here's a question for the tool aficionados...

I need to tighten the 5-turn knob on a multi-turn pot on my Tek SG504 (same thing is used on other gear like the Tek SG503 etc) and it seems I need a special little socket wrench..

Does anyone know what this sort of thing is called and where I can get one? I swear I've seen them before but I can't get the right keywords to find them in google..
I need one with an OD of about 8mm or so.

I would use circlip pliers, like these:

Damn fine idea AVG but a replaceable tip type like KD Tools made years ago with different size tips might be an even better idea.
This sort of thing:
https://www.amazon.com/Tools-446-Extrn-Snap-Pliers447/dp/B000CO7VL0/ref=pd_bxgy_sccl_2/145-0980204-0610157?pd_rd_w=wu3It&content-id=amzn1.sym.6ab4eb52-6252-4ca2-a1b9-ad120350253c&pf_rd_p=6ab4eb52-6252-4ca2-a1b9-ad120350253c&pf_rd_r=MEMA0VN2H8N0J5YR0WZ6&pd_rd_wg=MO0Uc&pd_rd_r=450d7915-9e52-489b-8455-308162c16339&pd_rd_i=B000CO7VL0&psc=1
Spare and accessory tips:
https://www.amazon.com/GEARWRENCH-448-Interchangeable-Point-Pliers/dp/B000GTOZH4/ref=pd_bxgy_img_sccl_2/145-0980204-0610157?pd_rd_w=HwDDj&content-id=amzn1.sym.6ab4eb52-6252-4ca2-a1b9-ad120350253c&pf_rd_p=6ab4eb52-6252-4ca2-a1b9-ad120350253c&pf_rd_r=TVHTJSEJ15GZ4F9HC2BR&pd_rd_wg=U7wGz&pd_rd_r=c2f0b2c1-a4f4-48a7-9e1b-14a18751ad58&pd_rd_i=B000GTOZH4&psc=1

[Robert763]

Pin spanner

You can make one with squre lugs by filing the end of a bit of mild steel tube.

Robert.

[TERRA Operative]

Thanks for the ideas! I'll try and see what I end up with. 

[m k]

There are also circlip pliers that can change their directions.
But be noted that if you need an accurate operation most of those are only sort of tools, and if you have a square slot a round tip can be nasty.
The tip being in center instead of a side is one nastiness more, something is again blocking and the tip can't reach the bottom of the slot.

[factory]

Here is the precision  tool I made, to remove one of those from a 1821A plugin.
Just a bit of steel plate from some consumer grade tat, modified with a hacksaw & file.

David

[DC1MC]

Here's a question for the tool aficionados...

I need to tighten the 5-turn knob on a multi-turn pot on my Tek SG504 (same thing is used on other gear like the Tek SG503 etc) and it seems I need a special little socket wrench..

Does anyone know what this sort of thing is called and where I can get one? I swear I've seen them before but I can't get the right keywords to find them in google..
I need one with an OD of about 8mm or so.

This ting ?
https://www.thorlabs.com/thorproduct.cfm?partnumber=SPW908

or these beauties:

https://www.amazon.sg/CRL-USW10-Universal-Spanner-Wrench/dp/B002DVSVTQ

Cheers,
DC1MC

[factory]

Next in line in my spring clean / downsizing is this Tektronix 453 scope.

50MHz, like new inside out, needs to be seen to be believed.
Comes with its cover which doubles as a storage compartment, has at least one period probe IIRC.
It's one of the "original" ones... I mean it's branded IBM. There is even some IBM yellow paper memorabilia in the storage compartment.

Sadly I bought it defective and it turns out it's not worth fixing. I lost my gamble. Lights up but no trace on the screen. Keeps blowing the HT fuse, and asI had it apart trying to troubleshoot the CRT HV section, I saw with my own eyes the HV transformer escape the magic smoke, which although I am no expert, can't be good.
Datasheet for the transformer is available, if you feel like winding your own transformers.. I don't.
Plus, the root cause of the problem might elsewhere and the transformer might only be a collateral damage.
I don't want to spend time nor money on this puppy, let's be honest.

It would be worth fixing if I were in love, but I am not.... I didn't want to buy it initially, but got persuaded by one of you, shall not give names. I fell for it eventually, because the seller was barely 10kms away from me, so no shipping cost involved...

So if you are a fan of these scopes, anf want to save its life, it's yours for the price of packing (20 Euros) and shipping via Mondial Relay (25/30 Euros to Germany IIRC),+ 10 Euros just to say I didn't give it away... (paid 40 Euros for it a year ago IIRC)

Can't sell it locally since a working one is not much more than the broken one I have... and the price of shipping and packing is a show stopper.

So the only thing that makes sense financially, is to take it apart and salvage a bucket load of like new parts that are worth way more than the non existing profit I could ever make from selling it, assuming anybody would volunteer to buy it.


So, In order not to repeat the mistake I made with the Tek 7504 I took apart the other day : are there any parts of particular interest in this scope, other than the obvious general purpose stuff (all the boards and switches/pots/trimmers/knobs etc) ?

The 4 feet at the back are all gone, disintegrated, as they always do on these scopes, I gather.
I think there must have been feet on the bottom as well, but they are all gone as well, only the metal work is left...

Maybe the trannystors for the vertical deflection ? They are mounted on the chassis. I guess they must have some good bandwidth.


So if you need some part to fix your scope, speak up....


@ Neomys : the current calibrator fixture ? I don't think it's the same model as the other Tek, so you might not be interested I guess.

If no-one takes it to restore, I would be interested in the front cover & CRT filter.

Be very careful if you recycle it into spares, the white ceramic transistor heat sink spacers are very likely to be made from Beryllium Oxide BeO, do not damage these, breathing in BeO dust will cause death.

Some of the transistors are matched pairs and there are a couple of tunnel diodes in there somewhere, tunnel diodes are expensive/difficult to obtain these days, can't easily get soviet ones thanks to you know who, they are very easy to damage too.

David

[Vince]

If no-one takes it to restore, I would be interested in the front cover & CRT filter.

OK noted...

Be very careful if you recycle it into spares, the white ceramic transistor heat sink spacers are very likely to be made from Beryllium Oxide BeO, do not damage these, breathing in BeO dust will cause death.

David

Oh... thanks for the warning... I do remember reading about this a while back about ancient TE, but I didn't think it would be present in such a "modern" scope....
Still can't get why they need radioactive stuff to mount a transistor...

Hopefully none of these transistor will be of interest so for safety's sake I will just leave them alone....

But, if it can kill me, it can kill other people further down the line... how is one supposed to dispose safely of these stuff ?
If I put it in the trash bin, it might get crushed inside the garbage collection truck, when it compacts the bags.
Then when the bags are burned in the incinerator, they will release their radioactivity probably...
It's scary... what does the law saw about how we should handle this ?! 

[wkb]

BeO is not radioactive. In dust form it is dangerous like asbestos fibres are dangerous.
It is not as if a whiff of the dust will make you drop dead on the floor.

[Messtechniker]

Come to think of BeO. I have salved a fom a
wrecked flatscreenTV a white heatsink.
Something I have never seen in 50 years+.
Initially I thought it was anodised aluminum.
But looking at a chipped spot - see pic -
I see that the material is solid white.
Since BeO is white. Might this be a BeO heat sink?

[ch_scr]

I have seen similar ceramic heatsinks in flat panel tv's as well. I suspect they would be of aluminum oxide ceramic?
Bonus question: Why make the heatsink of ceramic anyway? Surely, an aluminum one is cheaper, and with higher thermal conductivity to boot?
I suspect they might have had problems with the (ungrounded) metal one acting like an antenna and the ceramic one lowered EMI emissions?

[factory]

It's not just a heatsink but also an excellent insulator.
No idea about the stuff in consumer TVs, BeO is supposed to be very expensive.

There were white ceramic insulators used for the transistors in some PSUs we repaired at work, they were quite fragile though so doubt they were BeO.

David

[Messtechniker]

Found out now:
RS, for example, has these white ceramics heatsinks.
https://de.rs-online.com/web/p/kuhlkorper/1235627

[Neomys Sapiens]

It's on the side of the scope.

In this case, yes please!

[Vince]

Ah, see ! 

PM me your address bitte.

I will wait a few days before taking it apart, to let people who don't check TEA every single day a chance to ask for a part before the remains go to the scrappy.

[Vince]

BeO is not radioactive. In dust form it is dangerous like asbestos fibres are dangerous.
It is not as if a whiff of the dust will make you drop dead on the floor.

Thanks.

Looked it up in Wikipedia, good article there... it confirms 

https://en.wikipedia.org/wiki/Beryllium_oxide

Stuff is not radioactive and is only carcinogenic if you grind the part to create a sizeable amount of dust, then breathe that dust... but just snapping/breaking a part made from it.... is OK, no need to panic.

Used only because it's a good insulator as well as excellent heat conductor, second best behind Diamond.
So BeO is expensive but much less so than diamond.... so BeO wins.
Apparently still used for this reason in modern day electronic parts...
Hell they say it's even used in Magnetrons ! So that's what their white part is made of hmmm.....

So in short, it's fine.

I checked the Tek 453 scope parts list. They do mention materials for small hardware, but I never saw a mention of BeO.
Transistor insulators were either mentioned as being either plastic or nylon or Mica.

OK so I can calm down then... I am not doomed, just yet.

[TERRA Operative]

Anyone with a Tek SG504 and a small screwdriver want to do me a big favour? 


I need to see what's under the end cap on the rear of the oscillator assembly.... Gotta make sure mine goes back together properly after some extensive repairs and misplaced photos...

[Vince]

Some of the transistors are matched pairs and there are a couple of tunnel diodes in there somewhere, tunnel diodes are expensive/difficult to obtain these days, can't easily get soviet ones thanks to you know who, they are very easy to damage too.

David

Good idea... I looked in the parts list and found no less than x5 tunnel diodes ! In the trigger and sweep boards.
They are all the same model : " TD3A ", and all are hand selected for a current of 4.7mA

Searched Ebay, found only one for sale, in the USA, for 20 bucks ! 

https://www.ebay.co.uk/itm/275746604687?hash=item4033c7468f

OK it's a NOS, still bagged, Tektronix one... maybe an unbagged diode would be cheaper.

But rare and expensive indeed...

[factory]

BeO is not radioactive. In dust form it is dangerous like asbestos fibres are dangerous.
It is not as if a whiff of the dust will make you drop dead on the floor.

Thanks.

Looked it up in Wikipedia, good article there... it confirms 

https://en.wikipedia.org/wiki/Beryllium_oxide

Stuff is not radioactive and is only carcinogenic if you grind the part to create a sizeable amount of dust, then breathe that dust... but just snapping/breaking a part made from it.... is OK, no need to panic.

Used only because it's a good insulator as well as excellent heat conductor, second best behind Diamond.
So BeO is expensive but much less so than diamond.... so BeO wins.
Apparently still used for this reason in modern day electronic parts...
Hell they say it's even used in Magnetrons ! So that's what their white part is made of hmmm.....

So in short, it's fine.

I checked the Tek 453 scope parts list. They do mention materials for small hardware, but I never saw a mention of BeO.
Transistor insulators were either mentioned as being either plastic or nylon or Mica.

OK so I can calm down then... I am not doomed, just yet.

Some are just labelled "heat sink" with no description of the material, eg part #214-0317-00, the NSN lists state this is BeO.
This has been discussed here, but the OP never came back with pictures of the mystery part they found.
https://www.eevblog.com/forum/repair/tektronix-453-oscilloscope-beryllium-oxide-block/msg4205248/#msg4205248

David

[Neomys Sapiens]

After that prolongued dry spell, I might have been lucky today. IF they turn out to be ok, I have grabbed TWO Tektronix P5100 x100 probes for laughable 40€ including postage. The ground lead has been modified to connect both to a common ground and there are only those clips which are fitted, but that can be corrected.

[duckduck]

Say hi to my new friend ! 

He popped up on Leboncoin.fr a few days ago, just received it this evening.

Another Rochar Nixie meter, my 5th one now, this time it's a type A.1613

SPECS

Unlike my other Rochar meters that do just this or just that... this one does it all, a true DMM : does V and A both DC and AC, does resistance and capacitance.

It's also very compact indeed, so all in all it ticks all the boxes to be used often on the bench 

4 digits, 2,000 counts.

Goes up to 1,000V Vdc which will be perfect to check the B+ voltages when fixing my hollow-state Tek scopes.
Can go down to 0.1mV resolution on its 200m range, so it will be able to check ripple voltage as well.

Capacitance range only goes to 1uF but goes down to 200.0pF so 0.1pF resolution which is excellent.
I mean as much as I love my collection of fancy Metrix MX53/54/56 handheld DMM, they couldn't measure anything below 1 or 2nF to save their lives.

It has the printer output option !

Came with the original power cord... that can plug into that long obsolete power socket. Great, ready to go 

...snip...

Looks much nicer than the Solartron/Rochar version that was advertised over here a few days ago.
https://www.ebay.co.uk/itm/185825559487

My low ball offer wasn't enough, I didn't want to risk more due to the general poor condition, lack of power cable (seller seems to list the connectors separately for more ££), visible rust on the back makes me wonder it the tubes would be any good. 

Knowing it's got a Bakelite case is worse, as some sellers will deliver a box containing the chassis & a Bakelite jigsaw. 

Wonder how easy it is to service those boards behind the range/selector switches, looks tricky from your pictures. I does have some similarities to the A1466 in circuit design & layout, at least for the display counter boards.

Edit: picture added below, as ePay links tend to EOL after a few months.

David

That meter looks worse than the Antikythera mechanism. I assume that a storm washed it up on shore from a shipwreck?

EDIT (2nd try):

I didn't realize that / didn't know how I could display an existing picture in-line without attaching a new picture. It is possible!

[oz2cpu]

Kathrein MFK 85 TV/Radio Test Receiver 1994
I got this really cool unit at the last fleamarked, sad to see how badly it was thrown into a trashbin,
but it really works, contained 10 leaked D cell nicd, it receives RF video, and direct video in/out in COLOR :-)
super nice CRT size, it also contain a slow scan spectrum analyzer and printer and FM radio.
And how about teletext decoding, i was looking for a way to test that.

video about here : https://youtu.be/JB5W_2c1pcw